The length of time students needed in order to complete a statistics test followed a distribution that was approximately normal. The mean was 74 minutes, the standar deviation was 8 minutes. What proportion of students took more than one hour to complete the test?

And we can find this probability on this way:

And using the normal standard distribution table or excel and we got:

Step-by-step explanation:

Let X the random variable that represent the length of time student of a population, and for this case we know the distribution for X is given by:

Where and

We are interested on this probability

We can solve the problem using the z score formula given by:

If we apply this formula to our probability we got this:

And we can find this probability on this way:

And using the normal standard distribution table or excel and we got:

3, 12, 48, 384, 1536, 6144, 24576, 98304

step-by-step explanation:

just keep timing it by 4.

d) by the cross product property, ab^2 = bc multiplied by ad

step-by-step explanation:

we are given

in the given triangle abc

angle a is 90° and segment ad is perpendicular to segment bc

we can see that

triangle(abc) and triangle(abd) are similar because they have common side and same angle (90 degree)

so, triangles(abc) and abd are similar

since, they are similar

so, the ratio of their sides must be equal

we get

now, we can cross multiply

and we get

so, this could be step to prove it